Oxidation resistant alloy



United States Patent OXIDATION RESISTANT ALLOY James A. McGurty,Cincinnati, and Earl S. Funston,

Hamilton, Ohio, assignors to General Electric Company, a corporation ofNew York No Drawing. Filed Sept. 29,1959, Ser. No. 843,301

' 3 Claims. c1. 75-150 This invention relates to high temperature,oxidation resistant alloys and, more particularly, to binary alloys ofyttrium and beryllium.

Neutronic reactors, which are operated at high temperatures requirereflector and moderator materials,

air applications.

The problem existed to develop high strength, oxidation resistantberyllium alloys with suitable nuclear properties for reflector andmoderator applications. While beryllium metal has good strength atelevated temperatures, it was important to increase this strength forstructural members. Although inorganic beryllium compounds displayoxidation resistance at high temperatures, it would appear that thesecompounds have less thermal shock resistance than beryllium metal orberyllium alloys. I

The invention of the presentapplication provides high strength,oxidation resistant yttrium=berylliurn alloys which are useful in air attemperatures in excess of 2000 F.

It is an object of our invention to provide a high strength alloy.

'It is another object of our invention to provide an alloy which hassuperior oxidation resistance at temperatures in excess of 2000 F.

It is a further object of our invention to provide an alloy which issuitable for moderator or reflector application.

k In carrying out our invention in one form, from 15.0

to 50.0 weight percent of yttrium is combined with beryllium to providea high temperature, oxidation resistant alloy.

These and variousothcr objects, features and advantages of the inventionwill be better understood from the following description.

We discovered unexpectedly that the combination of yttrium and berylliumproduced alloys which had superior oxidation resistance and goodstrength in air at temperatures in excess of 2000" F. Furthermore, suchalloys were suitable for use in moderator and reflector structures. Thecombination of from 15.0 to 50.0 weight percent of yttrium withberyllium provided these extraordinary effects. While this Weightpercent of yttrium with beryllium improved substantially the oxidationresistance of this alloy, from 38.0 to 48.0 weight percent yttriumappeared to be the optimum amount of this addition.

During the research which led to the discovery of these oxidationresistant yttrium-beryllium alloys, a series of small, vacuum melted,rare earth element buttons were prepared. 'These alloy buttonscontaining from 15.0 to 50.0 weight percent yttrium and the balancebeing beryllium were heated in air at 2600 F. for various time periods.The specimens were then examined metallographically and weight changesmeasured. The data tabulated in Table I shows the excellent oxidationresistance of these alloys containing approximately 43.0 weight percentyttrium and the balance being beryllium. At 2600" F., both yttrium andberyllium would be oxidized completely in a short time period.

While other modifications of this invention which may 7 be employedwithin the scope ofthe invention have not been described, the inventionis intended to include all such as may be embraced within the followingclaims.

What we claim as new and desire to secure by Letters Patent of theUnited States is:

l. A binary alloy of yttrium and beryllium which consists of from 15.0to 50.0 weight percent yttrium and the balance being beryllium.

2. A binary alloy of yttrium and beryllium which consists of from 38.0to 48.0 weight percent yttrium and the balance being beryllium.

3. A binary alloy of yttrium and beryllium which consists ofapproximately 43.0 weight percent yttrium and the balance beingberyllium.

No references cited.

1. A BINARY ALLOY OF YTTRIUM AND BERYLLIUM WHICH CONSISTS OF FROM 15.0TO 50.0 WEIGHT PERCENT YTTRIUM AND THE BALANCE BEING BERYLLIUM.